Display screen or a portion thereof with transitional graphical user interface for a calendar application



FIG. 1 is a first image in a sequence of a front view of a display screen or a portion thereof with transitional graphical user interface for a calendar application; and,

FIG. 2 is a second image thereof.

The appearance of the transitional image transitions between the images shown in FIGS. 1-2. The subject matter in this patent includes a process or period in which an image transitions into another image. The process or period form no part of the claimed design.

The outermost broken line rectangle illustrates a display screen or portion thereof and forms no part of the claimed design. The remaining broken lines showing of text and other user interface elements is for the purpose of illustrating portions of the article and forms no part of the claimed design. 

CLAIM The ornamental design for a display screen or a portion thereof with transitional graphical user interface for a calendar application, as shown and described. 